Pedersen M M, Mogensen C E, Jørgensen F S, Møller B, Lykke G, Pedersen O
Second University Clinic of Internal Medicine, Medical Department, Kommunehospitalet, Aarhus, Denmark.
Kidney Int Suppl. 1989 Nov;27:S115-21.
Glomerular hyperfiltration may be a risk factor for late nephropathy. It has been shown that considerable protein restriction can lower glomerular filtration rate (GFR). To elucidate the effect of moderate protein limitation in type 1 (insulin-dependent) diabetics with normoalbuminuria, eight such patients were selected for the study (age 38 +/- 7 years SD, diabetes duration 21 +/- 9 years). The patients were randomized to follow, alternately, four weeks of their usual protein intake (19% of energy) and four weeks of a limited protein intake (12% of energy). Kidney function was investigated after the two dietary periods. GFR and renal plasma flow (RPF) were measured using a constant infusion technique (125I-iothalamate/131I-hippuran), and urinary albumin excretion (UAE) by radioimmunoassay. It was found that the limited protein diet reduced GFR from 146 +/- 23 to 132 +/- 24 ml/min/1.73 m2 (2P less than 0.005). A tendency towards a fall in RPF was seen (549 +/- 128 vs. 503 +/- 125 ml/min; 2P = 0.06), while total renal resistance rose from 0.17 +/- 0.03 to 0.20 +/- 0.05 mm Hg/ml/min (2P = 0.05). No significant changes in filtration fraction, UAE and blood pressure were seen. HbA1c, fructosamine, insulin dose and body weight were unchanged during the two diets; also serum protein, albumin, phosphate and calcium remained unaltered. Serum urea was significantly reduced on the limited protein intake. Patients were generally pleased with the limited protein diet. Thus, limitation of the often high protein intake in diabetics might be valuable and realistic. The long-term renal protective effect remains to be investigated.
肾小球高滤过可能是晚期肾病的一个危险因素。研究表明，严格的蛋白质限制可降低肾小球滤过率（GFR）。为阐明适度蛋白质限制对1型（胰岛素依赖型）正常白蛋白尿糖尿病患者的影响，选取8例此类患者进行研究（年龄38±7岁，标准差，糖尿病病程21±9年）。患者被随机分组，交替进行四周的常规蛋白质摄入量（占能量的19%）饮食和四周的有限蛋白质摄入量（占能量的12%）饮食。两个饮食阶段后对肾功能进行研究。采用持续输注技术（125I - 碘肽酸盐/131I - 马尿酸）测量GFR和肾血浆流量（RPF），通过放射免疫测定法测量尿白蛋白排泄量（UAE）。结果发现，有限蛋白质饮食使GFR从146±23降至132±24 ml/min/1.73 m2（P<0.005）。观察到RPF有下降趋势（549±128对503±125 ml/min；P = 0.06），而总肾阻力从0.17±0.03升至0.20±0.05 mmHg/ml/min（P = 0.05）。滤过分数、UAE和血压未见显著变化。两种饮食期间糖化血红蛋白（HbA1c）、果糖胺、胰岛素剂量和体重均未改变；血清蛋白、白蛋白、磷酸盐和钙也保持不变。有限蛋白质摄入时血清尿素显著降低。患者总体上对有限蛋白质饮食感到满意。因此，限制糖尿病患者通常较高的蛋白质摄入量可能是有价值且切实可行的。其长期肾脏保护作用仍有待研究。
